What you need for this:
1 Police Car with policemen (i'm starting to forget names)
4 Equipment Vehicles (In 3 Vehicles 3 firemen, and in the fourth vehicle 1 firemen.)
1 Engineer's Car (With Engineer of course )
4 Water Tenders (Also in each vehicle 3 firemen
2 Medical Busses with in each bus 3 doctors and 1 paramedic(I hope i'm saying it right )
1 Fire Ladder with Fireman (in Smoke equipment or something like that) in it.
This should do it
First of all, put the 3 Equipment Vehicles (with firemen) at the Head Entrance of the Airport Terminal, also put the Police Car right there,
When you did that, put the Engineer's Car at the gate to open it, when the gate is open put the Water Tenders around the plane and the tower, also put the first bus at the Head Entrance and the other bus at the little airplane,
Place the last Equipment Vehicle at the little airplane, and operate the Fire Ladder at the Airplane, you also should have put your policemen at the entrance to make sure all of the vehicle's coming in can get away so there is no risk for more injuries and fire,
Now we placed al vehicles and the policemen, equip ALL firemen (except the one at the little Airplane) with Extinguishers (srry if i spelled it wrong ) and make sure the firemen at the Entrance are in the building, the other 6 firemen (from the Water Tenders) should extinguish the building from the outside, when other parts of the building (wich are connecting the airplanes) are on fire, you need to extinguish them inmediatly, put 5 of the firemen INSIDE the building at the place where the airplane crashed, Take the stairs and extinguish as fast as you can the little fires, the other 4 firemen should extinguish the stairs and the building at the edge of the entrance,
Use the firemen to open the cockpit of the little airplane and use the doctor to help the injuries, Once the 2 injuries are good enough to enter the bus, use your Paramedic to put them in the bus (same story, but you can use your firemen to to put the injured person in the bus, really). get the firemen out of the ladder and enter the airplane, put the Medical Bus close to the fire ladder and heal the injured people when they're out of the airplane (Only do this when the fires have calmed down,) once the Western Part of the building (you may know what i mean when you look at your minimap)is extinguished, put the remaining 5 firemen to help the southern part and make sure 4 firemen got no equipment left, put these 4 men in the Southwestern building and clear the debris, use the 4 firemen to help the injuries to the entrance (quick job), put the 4 injuries in the bus and go back to the Headquarters,
There should be some people out of the plane now, keep doing this untill all the passengiers are out of the plane. when doing this use all 9 firemen from the building to extinguish the plane (this can be done by entering the Southwestern building), once all of the injuries are in the bus (there should be 8 injured people in the bus right now) head back to the headquarters, extinguish the plane and your done with the mission (this should be done within a half our (aka. 11 minutes on the timer)).
I really hoped this guide helped you on this mission